1. Field of Technology
Embodiments disclosed herein relate to power supplies, and more specifically to a self setting power supply using negative output impedance.
2. Description of the Related Arts
Most power supplies deliver a desired voltage to a client circuit. This desired voltage (or “set point”) may either be static or can be dynamically controlled. For example, in power supplies for application processors in smartphones or other digital circuits, the processor may control the power supply voltage to be lower or higher depending on the computational workload or desired speed. In envelope tracking applications, a radio frequency (RF) transceiver or digital baseband circuit may control the set point of a power supply based on the instantaneous RF power being delivered by an RF power amplifier.
In a conventional radio frequency power amplifier system, the RF output power generally increases as the amplitude of RF input signal to the power amplifier increases. For power efficient operation, an envelope tracking technique may be used in which the supply voltage to the RF power amplifier is adjusted based on the amplitude of the RF input signal to ensure that the appropriate instantaneous power is delivered to the load in a power efficient manner. For example, a power supply controller may adjust the supply voltage to the minimum supply voltage that will still enable the power amplifier to achieve the appropriate instantaneous output power. However, conventional systems that utilize dynamically controlled set points still fail to optimize efficiency of the power supply.